technoguy

A smoke signal is a form of visual communication used over a long distance, developed both in the Americas and in China. By covering an open fire with a blanket and quickly removing it, a puff of smoke can be generated. With some training, the sizes, shapes, and timing of these puffs can be controlled. Puffs may be observed from long distance, apparent to anyone within its visual range. With this in mind, signalling stations were often created to maximise the viewable distance. Stone bowls used by Native Americans and the towers of the Great Wall of China are examples of signalling stations.